Ammendment: change of max_drift correction
Ammendment number: 10
Submitted by: Joachim Schrod <xitijsch@ddathd21.bitnet>
Date: 14 Nov 90


Reason for change:

The algorithm for the max_drift correction as given in section 2.6.2
makes too large movements within one word. The corrected algorithm is
the same as in DVItype.


Technical note:

The correction is given explicitely as the definition of the new
reference point. A +-1 algorithm would not work because larger errors
may occur in one movement.
   I have introduced the term |dist| which is the distance -- but
it's the inverse distance of the former algorithm! This was made
because I think that  round(Kh) + sign(dist)*max_drift  is a more
intuitive description as  round(Kh) - sign(dist)*max_drift .


The ammendment is given as a context diff, assuming draft 0.04b at
it's base. This new ammendment results in the draft 0.04c.

*** dvistd4b.tex	Wed Nov 14 19:05:08 1990
--- dvistd4c.tex	Wed Nov 14 19:06:51 1990
***************
*** 265,273 ****
  and subscripts to be printed consistently.
  
  After any horizontal movement, a final check is made as to
! whether $\abs(Kh-{\it hh})>{\it max\_drift}$. If it is, then $\it
! max\_drift$ is added or subtracted to $\it hh$ to bring it closer to
! $Kh$. A similar check is made with $\it vv$ and $v$. $\it
  max\_drift$ should be set to~2 for output devices with device
  units smaller than or equal to 0.005\in\ (0.127\mm), 1~for output
  devices with device units greater than 0.005\in\
--- 265,274 ----
  and subscripts to be printed consistently.
  
  After any horizontal movement, a final check is made as to
! whether $\it dist > max\_drift$ with $\it dist$ defined as
! $\abs({\it hh}-\round(Kh))$. If it is, then $\it hh$ is set to
! $\round(Kh) + \sign({\it dist}) \cdot {\it max\_drift}$.
! A similar check is made with $\it vv$ and $v$. $\it
  max\_drift$ should be set to~2 for output devices with device
  units smaller than or equal to 0.005\in\ (0.127\mm), 1~for output
  devices with device units greater than 0.005\in\

--- end of ammendment